#include <openssl/rand.h>
#include <openssl/bio.h>
using namespace std;
int main()
{
    BIO * b = nullptr;
    b = BIO_new_file("bio.txt","w");
    int len = BIO_write(b,"openssl",7);
    len = BIO_printf(b,"%d",10);
    BIO_free(b);
}